Some prescription drugs provide a controlled release of the active pharmaceutical ingredient (“API”) that they are intended to deliver. Controlled release can be a delayed release such as an enteric release in the intestines. It can be an extended release where release begins immediately or shortly after ingestion and continues, either at a constant rate or in some pattern, over an extended period of time, usually from about 6 to about 24 hours. Often this is accomplished using a controlled release coating. Not only are controlled release dosage forms, and especially extended release dosage forms, convenient for the patients as they can take fewer doses throughout the day, but they also help prevent patients from being exposed to too much of the API thereby potentially suffering side effects. However, drug abusers may be at any one time or over a short period of time frustrated by such coatings for that same reason: they may prevent one from obtaining high initial blood concentrations which can cause the very effect—the “high,” that the abuser is seeking to obtain.
Indeed, opioids such as oxycodone, are sometimes available as extended release dosage forms for oral administration. One such product is OXCONTIN® from Purdue Pharma L.P. Once swallowed, these types of tablets slowly release their dose of active ingredient over an extended period, often over 6-24 hours. Such an extended release might be accomplished using a coating of some type over the individual particles of the opioid.
However, people can abuse such tablets, using them as recreational drugs, by circumventing the extended release substructure or feature, in this example, the extended release coating. Indeed, a person can compromise this or some other extended release feature by crushing the dosage form through chewing or other means. This can crush any coating or other controlled release feature thereby allowing the release of a relatively large amount of the opioid sooner than intended into their systems once ingested.
Ways of making a dosage form more crush resistant/abuse resistant include those disclosed in U.S. Patent App. Pub. No. 2006/0104909 and 2006/0193914. Coating pharmaceuticals with various materials to achieve other objectives, such as taste-masking, extended release, easier swallowing, etc. are also known. See, for example, U.S. Pat. Nos. 5,178,878; 5,607,697; 6,024,981; 6,280,770; 6,368,625; 6,692,771; 6,740,341; and 2003/0180362.
Another way to circumvent controlled release coatings is to attempt to dissolve the dosage form in a solvent such as water or ethanol. The latter can be particularly dangerous as many prescription drugs should not be taken with alcohol. Depending upon the coating material used, the ethanol or water may act as a solvent, dissolving or eroding the coating and circumventing the intended controlled release. The resulting material can then be administered generally, orally, or in a syringe by a drug abuser.
There are several techniques which have been developed to deter this type of solvent abuse. One abuse deterrent system for oral opioid compounds is described in U.S. Published Application No. 2006/0177380. This disclosure describes a composition containing a gel forming polymer forming an obstacle to syringe uptake, and nasal/mucosal irritant that causes discomfort when excessive amounts of the active compound are inhaled. Such abuse-deterring systems are designed for the nasal or parenteral abuse routes. See also U.S. Patent App. Pub. Nos. 2006/0193914, 2006/0188447, 2006/0193782, 2006/0204573, 2002/0110595, WO2007/087452A2, U.S. Pat. Nos. 6,607,751 and 7,090,867.